Holography system rides single beam

Along with its promise of storing mammoth amounts of data, conventional holography technology presents developers with one big problem. It requires two light beams--for information and reference--that must be exposed from different directions. This setup makes the system bulky and complex and demands a transparent recording medium that generally cannot contain address data.

Hideyoshi Horimai and Yoshio Aoki of Optware Corp. think they have a better way. Their Holographic Versatile Disc (HVD) is based on the company's Collinear technology, which does away with that pesky second light beam. Optware's first Collinear system--with 200 Gbytes of storage for the professional broadcast and movie industries--is scheduled to sample this summer. It will be shown at the National Association of Broadcasters convention April 24 to 27 in Las Vegas.

Horimai, who founded Optware in 1999 and is now its CTO, broke through the hindrances holding back holography by sticking to the idea of a one-beam system using a disk medium that contains address information. The beam in his Collinear technology combines the information and reference beams on the same axis, while a disk with addressing information comes preformatted. Collinear technology makes it possible to build a terabyte-level disk system with a structure quite similar to today's optical-disk systems, he said.

President and CEO Aoki--like Horimai, a Sony Corp. veteran--handles standardization, alliances and management, which are indispensable if Optware's HVD is to establish a position in the industry. A European Computer Manufacturers Association technical committee is already working on standardizing the holographic information systems. And the HVD Alliance that Optware formed a year ago has expanded its membership from six companies to 18.

Aoki and Horimai recently sat down for a chat with EE Times Tokyo bureau chief Yoshiko Hara. Their interview was conducted in Japanese and translated by EE Times.

EE Times:People usually believe that a holography system uses two light beams coming from different directions. How did you come up with the idea for your Collinear holography system, which uses just one beam?

Hideyoshi Horimai: When Dennis Gabor invented the first holography system about 60 years ago, it was so-called in-line holography, in which the beams came from the same direction. Then, about 40 years ago, two-axis holography was invented and became the mainstream. At that time, crystal was the medium used for recording, so two-axis holography was suitable. But it was not suitable for disk applications.

The problem [in a one-beam system] was that the information and reference beams merged, and two-axis holography was a solution to separate them.

I studied magnetic holography and my master's thesis was on holography. In magnetic holography, I could cut the reference light and extract the information light by polarizing the two beams. Since then I had been thinking that there might not need to be two axes in holography.

Yoshio Aoki: In other words, engineers who have been developing holography systems started from the precondition that two beams were mandatory. We were newcomers and knew only about optical disks. For us, the decision from the start was to let there be one beam.